I also have Office 2007 but experiance no slow down problems while using it, I have been to the office site and downloaded each update, this you have to do seperate to the windows update
http://office.microsoft.com/en-us/downloads/default.aspx
I am sure you have probably done this already?
I have less memory then you and a slower processor, so I would’nt say you need to go out and buy more ram (be it the good or the cheap stuff.. what ever that means) DOA is getting confused with wine and ram